Contributions
Abstract: PB1951
Type: Publication Only
Background
Basophilia is a frequently observed condition in chronic myeloid leukemia (CML) but its etiopathogenesis is not completely clear. Basophilia may not only be an accompanying phenomenon of CML but it may play a pathogenic role in the disease development. The role of CCL3 inflammatory chemokine produced by basophils was described in CML. We have observed rebound basophilia (RB) – an increase in the relative proportion of basophils in WBC differential counts (WDC) in some CML patients within the first month of cytoreduction treatment with hydroxyurea and/or imatinib. For the purpose of this study, RB was defined as an increase of one or more percent of basophils in WDC (assessed by light microscopy or counter in cases where light microscopy WDC was not available) with respect to the initial assessment before cytoreduction.
Aims
The aim was to analyze the incidence and possible prognostic role of RB.
Methods
We have retrospectively analyzed the WDC of CML patients at our institution during the first month of treatment. Overall and progression-free survival (OS, PFS) were calculated according to the Kaplan-Meier methodology, the log-rank test was used to assess the difference in survival between RB positive and RB negative patients, and the Kruskal-Wallis test were used to assess the difference in continuous variables between the two groups.
Results
We have analyzed 41 female and 63 male patients of median age of 54 years (range
20–88), the median follow-up was 3.1 years (range 3.5 months – 10.9 years). There were 65 cases of RB including 7 patients who were not in the accelerated phase at diagnosis but fulfilled the criteria for CML acceleration with isolated RB over 20% during cytoreduction. Statistically significant association of RB with younger age (p=0.02) and the Sokal score (p=0.02) was documented. Spleen size (in cm below the costal margin) was significantly larger (p=0.02) in patients with RB (median = 5 cm) than in patients without RB (median = 0 cm) Younger patients with RB died more often after the progression of CML, while elderly patients without RB died more often due to comorbidity without CML progression. RB positive patients more frequently required the treatment with second generation tyrosine kinase inhibitors (TKI) due to the imatinib failure (38.9%) in comparison with the RB negative group (22%; p=0.06), however their response to the treatment was not compromised. We found no statistical difference in progression free survival between the RG positive and RB negative groups (63% vs 75%, p=0.346). The overall complete cytogenetic response rates at 6 months after treatment initiation (CCyR) were not different between the RG positive and RB negative (29 % vs. 16%, [FEpMC1] p=0.14). Patient with and without RB had similar rates of major molecular response after 12 months after treatment initiation (25% vs 34%, p=0.31).
Conclusion
RB may be encountered in about half of CML patients. Although RB may has been observed by many physicians, its cause is unknown. RB is associated with other CML risk features but it probably lacks an independent prognostic value. However, RB may have a role in the prognostic stratification of younger CML patients. Further experiments and studies in larger cohorts of patients are needed to reveal the causes of RB and to evaluate its possible prognostic role.
Supported by the grant of IGA_LF_2018_04
Session topic: 8. Chronic myeloid leukemia - Clinical
Keyword(s): Chronic myeloid leukemia
Abstract: PB1951
Type: Publication Only
Background
Basophilia is a frequently observed condition in chronic myeloid leukemia (CML) but its etiopathogenesis is not completely clear. Basophilia may not only be an accompanying phenomenon of CML but it may play a pathogenic role in the disease development. The role of CCL3 inflammatory chemokine produced by basophils was described in CML. We have observed rebound basophilia (RB) – an increase in the relative proportion of basophils in WBC differential counts (WDC) in some CML patients within the first month of cytoreduction treatment with hydroxyurea and/or imatinib. For the purpose of this study, RB was defined as an increase of one or more percent of basophils in WDC (assessed by light microscopy or counter in cases where light microscopy WDC was not available) with respect to the initial assessment before cytoreduction.
Aims
The aim was to analyze the incidence and possible prognostic role of RB.
Methods
We have retrospectively analyzed the WDC of CML patients at our institution during the first month of treatment. Overall and progression-free survival (OS, PFS) were calculated according to the Kaplan-Meier methodology, the log-rank test was used to assess the difference in survival between RB positive and RB negative patients, and the Kruskal-Wallis test were used to assess the difference in continuous variables between the two groups.
Results
We have analyzed 41 female and 63 male patients of median age of 54 years (range
20–88), the median follow-up was 3.1 years (range 3.5 months – 10.9 years). There were 65 cases of RB including 7 patients who were not in the accelerated phase at diagnosis but fulfilled the criteria for CML acceleration with isolated RB over 20% during cytoreduction. Statistically significant association of RB with younger age (p=0.02) and the Sokal score (p=0.02) was documented. Spleen size (in cm below the costal margin) was significantly larger (p=0.02) in patients with RB (median = 5 cm) than in patients without RB (median = 0 cm) Younger patients with RB died more often after the progression of CML, while elderly patients without RB died more often due to comorbidity without CML progression. RB positive patients more frequently required the treatment with second generation tyrosine kinase inhibitors (TKI) due to the imatinib failure (38.9%) in comparison with the RB negative group (22%; p=0.06), however their response to the treatment was not compromised. We found no statistical difference in progression free survival between the RG positive and RB negative groups (63% vs 75%, p=0.346). The overall complete cytogenetic response rates at 6 months after treatment initiation (CCyR) were not different between the RG positive and RB negative (29 % vs. 16%, [FEpMC1] p=0.14). Patient with and without RB had similar rates of major molecular response after 12 months after treatment initiation (25% vs 34%, p=0.31).
Conclusion
RB may be encountered in about half of CML patients. Although RB may has been observed by many physicians, its cause is unknown. RB is associated with other CML risk features but it probably lacks an independent prognostic value. However, RB may have a role in the prognostic stratification of younger CML patients. Further experiments and studies in larger cohorts of patients are needed to reveal the causes of RB and to evaluate its possible prognostic role.
Supported by the grant of IGA_LF_2018_04
Session topic: 8. Chronic myeloid leukemia - Clinical
Keyword(s): Chronic myeloid leukemia